In the literature part electrocatalaysis of organic molecules is discussed: the electrode material, ions and molecules in the liquid phase and the electrode potential applied have highest influence on the adsorption and oxidation of these molecules. The probability of a metal to be a suitable catalyst for a certain organic molecule can be estimated by using the molecular orbital theory of both phases.

The experimental part includes two published articles and auxiliary experiments with stepped single crystal electrodes. In the first publication, crossover through the Nafion 115 membrane as a function of time and performance in a PEFC for several organic molecules is studied.

Methanol as the smallest uncharged molecules has the highest crossover rate through the studied membrane, however, also it produces superior performance in a platinum ruthenium catalysed PEFC. Even if other molecules do not reach the current densities produced with methanol, the open circuit potential obtained with isopropanol is dramatically higher compared to methanol.

Consequently, in the second publication the oxidation of methanol, isopropanol and their mixtures has been studied on platinum single crystal electrodes. On Pt(111) the alcohol mixture produces higher current densities than pure alcohol solutions in acidic electrolytes (HClO4 and H2SO4). As a result stepped single crystals with Pt(111) terraces and steps of Pt(100) or Pt(110) configuration have also been studied. The only stepped surface which produced higher current densities has wide Pt(111) terraces and Pt(100) steps.

In addition, the oxidation of 2-propanol and alcohol mixture is studied with IR spectroscopy and the results indicated that both isopropanol and methanol co-adsorbed on the Pt(111) surface, however, the explanation for the higher activity of an alcohol mixture compared to the isopropanol oxidation is still under investigation..